Snow groomer with a variable snowchamber tiller assembly

ABSTRACT

A snow tiller ( 10 ) suitable for grooming ski hills, trails, or other areas, provides an adjustable snow housing assembly. A snow chamber ( 70 ) is formed between a ground shaping element ( 48 ) that has a rotatable drum ( 50 ) and a trailing finishing element ( 62 ) that is supported by a trailing bar bracket ( 84, 110, 130 ). The shape and/or volume of the snow chamber ( 70 ) can be adjusted by activating a finisher positioning mechanism ( 72 ), such as a hydraulic cylinder, to pivot the trailing bar bracket ( 84, 110, 130 ). A pair of connecting bars ( 98  and  100 ) from a pivot point about which the trailing bar bracket ( 84, 110, 130 ) pivots in an arc with respect to the snow surface, thus providing for precise positional control of the snow chamber ( 70 ).

[0001] This application is a continuation-in-part application of International application No. PCT/CA00/01501 filed Dec. 15, 2000, the contents of which are hereby incorporated by reference.

FIELD OF INVENTION

[0002] This invention relates to ground working devices, particularly snow grooming devices. More specifically, this invention relates to tillers for use with snow grooming vehicles for ski slopes.

BACKGROUND OF THE INVENTION

[0003] Ground working devices have long been used in agriculture to break up and till earth. Such devices, known as tillers, typically include a trailing assembly that has a rotating ground loosening unit and a smoothing or leveling board. The loosening unit can be subdivided into subassemblies connected by joint(s) to accommodate the changing contours of the ground.

[0004] This general concept has been adopted and modified to groom snow, especially ski slopes. Snow making and snow grooming has become an essential part of any successful ski center due to increased skier traffic, longer ski seasons, and variable weather conditions. As a result, snow groomers are becoming more sophisticated. Typical snow grooming vehicles are tracked vehicles, which provide traction across the snow and up and down hills. These vehicles are equipped with a number of attachments or devices to help in the snow grooming process.

[0005] Generally, a tracked snow vehicle has an inverted V-shaped or U-shaped plow on the front of the vehicle that collects snow from areas where there is too much and moves it to areas which are worn. The front implement can also rip up icy and encrusted slopes to create or renew trails and remove glacier surface ice. The front implement can include a toothed bar that is lowered by a pivoting ram to break up hard, icy slopes into large lumps. The tracks of the vehicle assist in breaking up the lumps. Attached to the rear of the vehicle is a snow tiller that grinds the lumps and surface and then smoothes the surface of the snow to restore it to skiing condition.

[0006] Snow tillers are frequently equipped with a drum formed as a rotating blade and a finishing member that trails behind the rotor. A snow chamber or housing is formed immediately behind the drum and under and in front of the finishing member to hold a volume of snow so that it can be worked more extensively by the tiller. The finishing member is usually a flexible mat or mats having grooved finishing elements provided at the rear of the tiller assembly to provide the final snow surface conditioning by smoothing or, alternatively, to provide a “corduroy” texture to the surface of the tilled snow.

[0007] By controlling the angle at which the finishing member is supported, the volume of the snow chamber can be changed. Accordingly, the amount of snow held in the snow chamber during tilling can be controlled and varied based on current snow conditions. For example, if the snow chamber is enlarged, snow held within the chamber can be worked by the tiller for a longer period of time. An example of a variable snow chamber is disclosed in U.S. Pat. No. 5,067,263, in which the angle of the trailing bar mounted on the flexible membrane that forms the outer bounds of the snow chamber is varied to retain more or less snow within the snow chamber. The disclosure of U.S. Pat. No. 5,067,263 is incorporated into this application by reference.

[0008] A prior art assembly similar to U.S. Pat. No. 5,067,263 is shown in FIGS. 11 and 12. A tiller 200 is typically driven by a vehicle such as a snow groomer (not shown). Tiller 200 includes a main frame 238 that is supported by the vehicle. Main frame supports a pair of cross beams 244 that hold a ground shaping element 248 that has a cutting drum 250 and a cover 252. Cutting drum 250 is driven to rotate thereby breaking up ice chunks, hard pack and other lumps of snow or ice to produce a softer, more desirable and uniform surface. A finishing element 262 extends from ground shaping element 248 and is formed as a flexible mat that smoothes out the ground ice and snow. A snow chamber 270 is formed between the ground shaping element 248 and the finishing element 262 in which snow and ice is held while the cutting drum 250 works the ice and snow. Finishing element 262 has a trailing bar 280 that is supported by a positioning mechanism 272 that includes a hydraulic cylinder 278 and a support bar 276. As seen in FIGS. 11 and 12, trailing bar 280 can be tilted backward and forward by actuating hydraulic cylinder 278 within a limited range of movement.

[0009] Known variable geometry snow tillers produce acceptable, and at times even outstanding, snow surface finishes over a wide range of snow conditions. However, moist to wet snow conditions pose special considerations and handling requirements. In particular, it is difficult to process wet or moist snow effectively once it has been through the cutting drum, resulting in an unacceptable snow surface finish.

[0010] The inventor of this application believes that the poor performance results when snow is held too long in the variable geometry snow chamber. Since moist to wet snow is the ideal type of snow to make snowballs, snow tumbling in the snow chamber, defined as the area between the cutting drum and trailing bar, begins to agglomerate into lumps. These lumps continue to increase rapidly in size until the entire chamber section is filled with lumps. After initially filling the snow chamber, the lumps continue to become more and more compacted and correspondingly harder. The trailing bar tends to retain the lumps until they reach a high degree of compaction, producing lumps of almost rock-like hardness. The growing volume of these hard lumps of compacted snow eventually forces the lumps to pass under the trailing bar and be pressed into the groomed snow surface. The presence of these hard lumps, which may be of substantial size, results in a groomed snow surface that is not satisfactory for most snow sports. Therefore, there is a need to better control the assembly under such snow conditions to address the problem of forming hard lumps during snow conditioning.

SUMMARY OF THE INVENTION

[0011] An aspect of this invention is to provide a tiller that can be modified in response to snow conditions.

[0012] Another aspect of this invention provides a tiller having a snow chamber in which the volume and/or geometry can be varied.

[0013] A further aspect of this invention provides a snow chamber that can be finely adjusted.

[0014] An additional aspect of this invention comprises providing a controller that allows an operator to selectively change the chamber shape for grooming.

[0015] Embodiments of this invention provide a tiller assembly for shaping a surface, comprising a main frame, a ground shaping element carried by the main frame, and a finishing element supported by the main frame and arranged to trail behind the ground shaping element over the surface. A chamber having a volume is formed between the ground shaping element and the finishing element. A bracket is secured to the finishing element, and a driven member connected between the main frame and the bracket that moves the bracket in an arc with respect to the surface to thereby change the volume of the chamber.

[0016] This invention also provides a tiller assembly for shaping a surface, comprising a main frame, a ground shaping element carried by the main frame, and a finishing element supported by the main frame and arranged to trail behind the ground shaping element over the surface. A chamber having a volume is formed between the ground shaping element and the finishing element A pivot arm extends outwardly from the ground shaping element, and a bracket is secured to the finishing element. A pivoting connector is pivotally attached between the bracket and the pivot arm. A driven member is connected between the main frame and the bracket that causes the bracket to pivot with respect to the pivot arm.

[0017] This invention additionally provides a tiller assembly for shaping a surface, comprising a main frame, a ground shaping element carried by the main frame, and a finishing element supported by the main frame and arranged to trail behind the ground shaping element over the surface. A chamber having a volume is formed between the ground shaping element and the finishing element. A bracket is secured to the finishing element. A pivoting connector has two ends with one end pivotally attached to the bracket. A driven member is connected between the main frame and the other end of the pivoting connector that causes both ends of the pivoting connector to pivot and swing the bracket, thereby changing the volume of the chamber.

[0018] The invention further relates to a method of working the surface of the ground, comprising providing a tiller assembly having a ground shaping element and a finishing element with a chamber defined therebetween, wherein the finishing element is supported by a bracket. The method includes tilting the finishing element to change the volume of the chamber by moving the bracket in an arc with respect to the surface of the ground. The ground shaping element is operated to grind the surface, and the tiller assembly is driven across the surface to drag the finishing element over the surface and provide a finished texture to the ground.

[0019] It is to be understood that the invention described herein can be varied in a number of ways and is not restricted to the particular embodiments described herein. The invention is intended to generally include a variety of equipment arrangements wherein the volume and shape of the snow housing can be selectively set and controlled.

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The invention will be described in greater detail in conjunction with the following drawings wherein:

[0021]FIG. 1 is a side view of a tracked vehicle with a tiller in accordance with an embodiment of the invention attached thereto;

[0022]FIG. 2 is an enlarged partial side view of the tiller shown in a first position in accordance with an embodiment of the invention;

[0023]FIG. 3 is an enlarged partial side view of the tiller of FIG. 2 shown in a second position;

[0024]FIG. 4 is a schematic view of the tiller of FIG. 2 showing the change between the first and second positions;

[0025]FIG. 5 is a partial perspective view of a support assembly for the tiller in accordance with an embodiment of the invention;

[0026]FIG. 6 is a partial perspective view of another support assembly for the tiller in accordance with an embodiment of the invention;

[0027]FIG. 7 is a partial perspective view of the preferred support assembly for the tiller in accordance with another embodiment of the invention;

[0028]FIG. 8 is a side view of the tiller in the first position according to the embodiment shown in FIG. 7;

[0029]FIG. 9 is a side view of the tiller in the second position according to the embodiment shown in FIG. 7;

[0030]FIG. 10 is schematic side view of the tiller moving between the first and second positions in accordance with the preferred embodiment of FIG. 7;

[0031]FIG. 11 is a partial side view of a tiller in accordance with the prior art in which the tiller is in a first position; and

[0032]FIG. 12 is a partial side view of the prior art tiller of FIG. 7 in a second position.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

[0033] The invention is described with particular reference to a snow groomer including a snow tiller. The detailed description of the snow groomer as the vehicle with which the tiller is used is provided for purposes of illustration only and is not intended to be a limiting embodiment.

[0034]FIG. 1 shows an assembly 1 including a ground working vehicle 12 with a tiller 10 attached thereto in accordance with an embodiment of the invention. Ground working vehicle 12 in this case is a tracked vehicle, commonly called a snow groomer, that functions as the power source for tiller 10.

[0035] Vehicle 12 has a cab 14, in which an operator can sit and drive the vehicle and operate the controls for the various implements connected to the vehicle. The drive mechanism for vehicle 12 is a pair of rotatable tracks 16 with one track 16 disposed on each side of the vehicle body. Vehicle 12 has a front implement 18, in this case a hydraulically controlled plow 20, and a rear implement, which in this case is tiller 10. Vehicle 12 is especially adapted for driving on snow, but of course could be any type of vehicle. Additionally, a variety of accessories and attachments may be used with the vehicle either on the front or rear, including for example a front digger rather than a front plow. Further, if desired, only a rear implement could be used.

[0036] Vehicle 12 is equipped with appropriate attachment mechanisms 22 and 24 on the front and/or back of the vehicle, respectively, to provide power and structural connections to such front and/or rear implements. Cab 14 includes a control panel 26 connected to a controller, shown schematically in FIG. 1, to control operations of the vehicle and its implements. Of course, if desired or if a different type of vehicle is used, control panel 26 could be provided elsewhere on the vehicle, on the tiller itself, and/or at multiple locations. The control panel 26 can be of any known form suitable for actuating the implements and selecting various functions for the implements. The controller can be implemented in any known type of operating control system. For example, the control logic could be hard wired into the central logic system of the vehicle or implemented as a plug-in or through software installation.

[0037] Attachment mechanism 24 is an articulated joint for connecting tiller 10 to a power source, in this case vehicle 12, and can be a three point hitch 26 and a hydraulically controlled lifting mechanism 28. The hydraulic lifting mechanism 28 includes a main tow bar 30 and a driven hydraulic cylinder 32 that can be controlled to raise tiller 10 from the surface of the ground. A hydraulic tilt cylinder 34 is provided to change the depth at which tiller 10 works the surface. Any other suitable connecting mechanism could also be employed and could optionally include the lifting mechanism, if desired. Other desired connections could be used including electric, pneumatic, optical or communication connections to control and operate different operating functions of the tiller.

[0038] Tiller 10 includes a support frame 36 connected to the lifting mechanism 28. The support frame 36 has a main horizontal frame 38 in the form of a box beam, I beam, channel beam or any strong structural beam type member. An upper snow guard 40, typically two separate panels, is attached to main frame 38 to prevent snow from blowing from the tracks 16 over the tiller assembly 10 onto the finished snow surface. A pair of cross beams, of which only one beam 44 is shown, extend rearwardly from main frame 38 and support a ground shaping element 48.

[0039] Ground shaping element 48 includes a rotatable drum 50 with cutting teeth and a cover 52. Cover 52 creates a housing for rotatable cutting drum 50 and includes end caps 51. Cover 52, which is best seen in FIG. 7, can form a single housing or a series of housings along the length of ground shaping element 48. Ground shaping element 48 has a longitudinal axis about which drum 50 rotates and is oriented perpendicular to a direction in which tiller 10 is driven. A drive train, in this case in the form of a gear box, is connected to rotatable drum 50 to selectively rotate drum 50 to grind or otherwise shape the ground or material beneath drum 50. Drum 50 rotates to break up ice chunks, hard pack, or other undesirable types of snow, or ice as the case may be, to produce a softer, more desirable surface.

[0040] Extending from cover 52 of ground shaping element 48 is a finishing element 62. Finishing element 62 includes a flexible mat, for example a rubber or heavy polymeric sheet, that is positioned to drag behind ground shaping element 48. The design, surface, and weight of the mat as it being drawn across the surface, smoothes the ground out behind ground shaping element 48 after the ground has been cut or shaped. It is preferred that the trailing mat be flexible at anticipated operating temperatures so that it may more closely follow the contour of the surface of the ground.

[0041] The outer edge of finishing element 62 can be shaped, for example with serration, and/or can include finishing formations 66, which are blocks or strips attached to the lower surface of or molded into the flexible mat, both of which create texture in the finished surface when tiller 10 is driven across the surface of the ground. Finishing element 62 may also be formed as a board or membrane that optionally has rows of finishing elements, preferably formed of polyethylene or plastics but may also be formed of steel, fiberglass, or other suitable materials in a variety of profiles. The texture formed in the snow surface by finishing element 62 is known as a “corduroy” surface, especially in the snow grooming field, and includes a series of striations formed on the surface of the snow. The texture can be varied, of course, by varying the type and/or shape of edge 64 of finishing element 62 and/or the shape, type and size of finishing formations 66.

[0042] A snow chamber 70 is defined beneath cover 52 and between rotating drum 50 and finishing element 62. Snow is retained within snow chamber 70 and worked by rotating drum 50 before being smoothed by finishing element 62. As described below, the shape, and hence the volume, of the snow chamber 70 can be varied in accordance with this invention.

[0043] A finisher positioning mechanism 72 is provided to rotate finishing element 62 relative to the ground and to adjust the shape of finishing element 62 so as to control the volume of the snow chamber 70. Preferably, two finisher positioning mechanisms 72 are provided on each side of tiller 10. However, there is no specific number of mechanisms required, and any number from one or more than two is possible. Finisher positioning mechanism 72 extends from cover 52, or as an extension of cross beams 44, and is secured to finishing element 62 by a trailing bar 80, which is preferably semi-rigid so as to conform to the terrain over which the tiller passes.

[0044] As described in detail below, finisher positioning mechanism 72 includes a driven member 78, such as a hydraulic cylinder, and a trailing bar bracket 84 that is pivotally attached to an extension of main frame 38 so as to allow trailing bar 80 to pivot with respect to main frame 38. As described herein, trailing bar bracket 84 is preferably supported by a pivot arm 76, which is attached to housing or cover 52, and adjusted by finisher positioning mechanism 72.

[0045] As seen in FIGS. 2 and 3, trailing bar 80 is secured to finishing element 62 on one side of the mat with a smoothing board 82 secured to the other side of the mat. It is possible to use only the trailing bar 80 without smoothing board 82. It is also possible to use only smoothing board 82 as the attachment point through the mat for finisher positioning mechanism 72.

[0046] In this embodiment, trailing bar 80 is supported by trailing bar bracket 84. As seen in FIG. 5, bracket 84 preferably includes a generally horizontal bracket bar 86 and a pair of angled support legs 88 and 90, respectively. Bracket bar 86 can be formed as a box beam for strength or can have any conventional structural shape, including an I-beam or plate. Similarly, support legs 88 and 90 are shown as plate-like brackets, but can be formed of any known structural shape. As seen in FIGS. 2 and 3, finisher positioning mechanism 72 is secured to bracket bar 86. (In FIG. 5, finisher positioning mechanism 72 is removed to more clearly show the trailing bar 80 support structure.)

[0047] As noted above, bracket bar 86 is also secured to pivot arm 76 that extends outwardly from ground shaping element 48. In this case, pivot arm 76 extends from cover 52 and is secured to cross beam 44, which is supported by main frame 38. As seen in FIGS. 2 and 3, pivot arm 76 is secured at two fastening points 92 and 94 to cross beam 44 so that pivot arm 76 extends rigidly outward and cannot move. Pivot arm 76 is coupled to bracket bar 86 with a support bracket 96 that extends from below bracket bar 86, as seen in FIG. 5, and rotatably supports a pair of rigid connecting rods 98 and 100.

[0048] Connecting rods 98 and 100 are arranged in longitudinal alignment with respect to the front to back direction of the tiller. Connecting rods 98 and 100 are rotatably supported at each end. For example, connecting rod 98 is rotatably supported by support bracket 96 at one end and by pivot arm 76 at the other end. Connecting rod 100 is similarly supported. Pivot arm 76 is configured with a pair of spaced, parallel support fingers 102 and 104 at its outwardly extending end to support the ends of connecting rods 98 and 100 therebetween. Of course, any secure form of attachment can be provided at any point on trailing bar bracket 84 that allows relative pivotal movement between pivot arm 76 and trailing bar bracket 84.

[0049] As seen in FIGS. 2-4, the lower ends of connecting rods 98 and 100 are secured to pivot arm 76 adjacent to each other while the upper ends of connecting rods 98 and 100 are secured to support bracket 96 spaced from each other. By this, connecting rods are not arranged parallel to each other along their length. As seen in FIG. 2, connecting rod 98 is also longer than connecting rod 100. However, the connecting rods could be the same length or connecting rod 100 could be longer than connecting rod 98. By any of these arrangements, the four ends of the connecting rods 98 and 100 define the corners of a trapezoid. Ideally, the trapezoid is shaped to minimize the amplitude experienced by the trailing bar 80 when it is adjusted.

[0050] Alternatively, as seen in FIG. 6, the trailing bar 80 support structure can be a U-shaped bracket 110 with upstanding side walls 112 and 114 and a connecting web 116 that is directly secured to trailing bar 80. In this case, pivot pins 118 and 120 are provided to support the upper ends of connecting rods 98 and 100. The lower ends of connecting rods 98 and 100 are secured at pivot points to a channel bracket 122. Channel bracket 122 is used in place of pivot arm 76 and is directly secured to finisher positioning element 72. The relative relationship between connecting rods 98 and 100, as described above with respect to FIG. 5, remains the same. Bracket 110 can be used alone or in combination with bracket 84. When used in combination, bracket 110 can be used as a stabilizer. In this case, for example, a pair of brackets 84 can be secured to trailing bar 80 along with three brackets 110 alternated at each side of bracket 84 to provide a consistent shape to snow chamber 70.

[0051] In operation, finisher positioning mechanism 72 is operated to selectively move trailing bar 80 with respect to the main frame 38 of tiller 10. First, driven member 78 is actuated. Any driving force member is suitable for use in this invention, for example a gear driven rod or ratchet assembly, pneumatic cylinders, motor driven devices or rotating devices, used singly or in combination. However, in this embodiment, a hydraulic cylinder is used as the driven member 78. So, hydraulic cylinder 78 is actuated using any suitable control system and hydraulic assembly. Cylinder 78 can be driven using a separate hydraulic system or can be driven using the hydraulic system in place in the snow groomer. For example, parent PCT application PCT/CA00/01501 describes several suitable hydraulic control schemes that vary from manual to automatic.

[0052] To change the volume and/or shape of the snow chamber 70, the operator of the vehicle 12 actuates hydraulic cylinder 78 to move between a first position, shown in FIG. 2, and a second position, shown in FIG. 3, and vice versa The terms first and second are used only as relative terms and do not imply a particular order. The first position is the open or fully extended position in which the rod of the hydraulic cylinder 78 is fully extended The second position is the closed or filly retracted position in which the rod of the hydraulic cylinder 78 is full retracted.

[0053] Referring to FIG. 4, the finisher positioning mechanism is shown moving from the first position (in dotted lines) to the second position. As can be seen in FIG. 4, because of the arrangement of connecting rods 98 and 100, with the trapezoidal configuration and four pivot points, retracting hydraulic cylinder 78 causes bracket bar 86 (to which the end of hydraulic cylinder is connected) to move in an arc α. This causes trailing bar 80 to also move in an arc with respect to the surface of the ground, in this case snow. Moving trailing bar 80 causes finishing element 62 to change shape. As seen in FIG. 4, finishing element 62 changes from a relative straightened profile to a convex profile with respect to the snow surface, thus reducing the volume of snow chamber 70. Pivoting trailing bar 80 in an arc allows a greater scope of control in controlling the volume of snow chamber 70. By the arrangement described above, trailing bar 80 in effect swings around pivot bar 76 in response to movement of hydraulic cylinder 78.

[0054] The embodiment shown in FIG. 6 works in the same way in that trailing bar 80 swings from bracket 110 in response to movement of hydraulic cylinder 78.

[0055] Referring to FIGS. 7-10, which show the preferred embodiment of this invention, trailing bar 80 is supported by an arch shaped rigid bracket 130. Bracket 130 is formed of a metal rod or tube, for example, bent into an arch shape with each end of the arch secured to a channel bracket 132 and 134, respectively. Any number of brackets 130 may be used along the length of trailing bar 80. For example two to four brackets may be used. At the apex of the arch bracket 130, a support bracket 136, similar to support bracket 96 in the embodiment shown in FIG. 3, is provided that connects arch 130 to driven member 78 and pivot arm 76. Between pivot arm 76 and support bracket 136, connecting rods 98 and 100 extend. As described above, each connecting rod 98 and 100 is rotatably supported at its respective ends, which are arranged to define a trapezoid.

[0056]FIG. 8 shows the driven member 78 in the fully extended position, which moves the finisher positioning mechanism 72 into the first position. Due to the trapezoidal arrangement of connecting rods 98 and 100, trailing bar 80 is tilted with respect to the snow surface. FIG. 9 shows the driven member 78 in the fully retracted position, which moves the finisher positioning mechanism 72 into the second position. As seen in FIG. 10, actuation of driven member 78 swings support bracket 136 in an arc, pivoting driven member 78 with respect to cross beam 44 and causing connecting rods 98 and 100 to rotate with respect to pivot arm 76. As a result, bracket 130 swings and tilts trailing bar 80.

[0057] To help maintain the shape of snow chamber 70, a pressure plate 140 is used in this embodiment to press the end of finishing element 62 down and reduce bulging in the snow chamber 70. Snow chamber 70 is shown with a relatively flat upper surface in FIG. 8, which is an ideal shape. However, in practice, chamber 70 typically has an upper concave shape that bulges upwardly due to snow accumulation within chamber 70. Pressure plate 140 extends from housing or cover 52 and can optionally be biased downwardly as seen in FIG. 9. A conventional biasing mechanism can be used, such as a spring hinge, that allows pressure plate 140 to pivot upwardly when trailing bar 80 is tilted upward and snow chamber 70 is enlarged and then return to a downward oriented position. Of course, pressure plate 140 can be used with any of the embodiments disclosed herein.

[0058] A tiller designed and controlled in accordance with any of the above schemes can be used to groom surfaces, for example ski trails, in controlled profiles and be responsive to variable snow and weather conditions. The degree of work that the tiller does on the snow can be controlled by controlling the shape and volume of the snow housing. By this, snow grooming can be controlled in different areas of the trail and at different times by the operator during grooming.

[0059] In addition to the snow housing adjustments, the tiller may be provided with a range of other adjustments to address differing snow conditions on the same hill on the same day in different areas. Preferably, the operator would be able to activate all of the controls to move the various cylinders or make other adjustments to the operation of the tiller from the security of the cab. It is possible to arrange the system so that an operator would only need to glance in the rear view mirror to discern if the correct quantity and quality of snow is being left behind.

[0060] Further, this invention can be used in combination with the profile adjustment system disclosed in parent PCT application PCT/CA00/01501 by using the same or a different control scheme.

[0061] It is to be understood that the essence of the present invention is not confined to the particular embodiments described herein but extends to other similar devices that employ a variable snow housing assembly to control snow conditioning 

What is claimed is:
 1. A tiller assembly for shaping a surface, comprising: a main frame; a ground shaping element carried by the main frame; a finishing element supported by the main frame and arranged to trail behind the ground shaping element over the surface, wherein a chamber having a volume is formed between the ground shaping element and the finishing element; a bracket secured to the finishing element; and a driven member connected between the main frame and the bracket that moves the bracket in an arc with respect to the surface to thereby change the volume of the chamber.
 2. The tiller assembly of claim 1, wherein the driven member causes the bracket to pivot about a point spaced from the bracket.
 3. The tiller assembly of claim 1, further comprising a pivot arm supported by the main frame, wherein the bracket is connected to the pivot arm and pivots with respect to the pivot arm.
 4. The tiller assembly of claim 3, further comprising a connector having one end pivotally connected to the bracket and another end pivotally connected to the pivot arm.
 5. The tiller assembly of claim 4, wherein the driven member is movable between a first position and a second position thereby swinging the bracket with respect to the pivot arm.
 6. The tiller assembly of claim 4, wherein the connector includes a pair of connecting rods both arranged to pivot about pivot axes substantially parallel to the ground shaping element.
 7. The tiller assembly of claim 4, wherein the connector includes a pair of connecting rods aligned with the driven member.
 8. The tiller assembly of claim 4, wherein the connector includes a pair of connecting rods connected between the bracket and the pivot arm with four pivot points arranged to define a trapezoid.
 9. The tiller assembly of claim 1, wherein the bracket includes an arch shaped rod.
 10. The tiller assembly of claim 1, wherein the bracket includes a bar spaced from and substantially parallel to a top surface of the finishing element.
 11. The tiller assembly of claim 1, further comprising a connector disposed between the bracket and the driven member.
 12. The tiller assembly of claim 1, wherein the bracket includes a pair of side walls and a pivot member extending therebetween, wherein the driven member is pivotally attached to the pivot member.
 13. The tiller assembly of claim 12, further comprising a connector disposed between the pivot member of the bracket and the driven member.
 14. The tiller assembly of claim 13, wherein the connector includes a pair of connecting rods and the pivot member includes a pair of pivot pins, each connecting rod pivotally connected between a pivot pin and the driven member.
 15. The tiller assembly of claim 14, wherein each connecting rod has opposed ends, the ends arranged to define a trapezoid.
 16. The tiller assembly of claim 1, further comprising a trailing bar connected to the finishing element, wherein the bracket is coupled to the trailing bar.
 17. The tiller assembly of claim 1, further comprising a plurality of brackets and a plurality of driven members.
 18. The tiller assembly of claim 1, further comprising a power connection on the frame for connection to a power source, the power connection attached to the driven member.
 19. The tiller assembly of claim 1, wherein the driven member is a hydraulic cylinder.
 20. The tiller assembly of claim 1, further comprising a controller in communication with the driven member that controls movement of the driven member and thereby controls the volume of the chamber.
 21. The tiller assembly of claim 20, wherein the controller includes a hydraulic system connected to the driven member.
 22. The tiller assembly of claim 1, wherein the ground shaping element includes a rotatable drum with cutting teeth.
 23. The tiller assembly of claim 1, wherein the tiller assembly is a snow tiller and the ground shaping element is a rotatable drum with a cover.
 24. The tiller assembly of claim 1, wherein the finishing element is a flexible mat with finishing formations that create a texture in the surface.
 25. The tiller assembly of claim 1, in combination with a vehicle.
 26. The tiller assembly of claim 25, wherein the vehicle is a tracked vehicle and the tiller is a snow tiller.
 27. A tiller assembly for shaping a surface, comprising a main frame; a ground shaping element carried by the main frame, wherein the ground shaping element has a longitudinal axis; a finishing element supported by the main frame and arranged to trail behind the ground shaping element over the surface, wherein a chamber having a volume is formed between the ground shaping element and the finishing element; a pivot arm extending outward from the ground shaping element; a bracket secured to the finishing element; a pivoting connector pivotally attached between the bracket and the pivot arm; and a driven member connected between the main frame and the bracket that causes the bracket to pivot with respect to the pivot arm to thereby change the volume of the chamber.
 28. The tiller assembly of claim 27, wherein the pivoting connector includes a pair of connecting rods.
 29. The tiller assembly of claim 28, wherein the connecting rods are aligned in a direction substantially perpendicular to the longitudinal axis.
 30. The tiller assembly of claim 28, wherein each connecting rod has a first end and a second end, wherein the first ends of adjacent connecting rods are spaced apart at a first distance and the second ends of adjacent connecting rods are spaced apart at a second distance different from the first distance.
 31. The tiller assembly of claim 27, wherein the bracket includes an arch shaped rod.
 32. The tiller assembly of claim 27, wherein the bracket includes a generally horizontal bar and a pair of support legs that space the bar from the finishing element, the driven member being attached to the bar.
 33. The tiller assembly of claim 27, further comprising a trailing bar connected to the finishing element, wherein the bracket is coupled to the trailing bar.
 34. The tiller assembly of claim 27, further comprising a power connection on the frame for connection to a power source, the power connection attached to the driven member.
 35. The tiller assembly of claim 27, wherein the driven member is a hydraulic cylinder.
 36. The tiller assembly of claim 27, further comprising a controller in communication with the driven member that controls movement of the driven member and controls the volume of the chamber.
 37. The tiller assembly of claim 27, wherein the finishing element is a flexible mat with finishing formations that create a texture in the surface.
 38. The tiller assembly of claim 27, further comprising a plurality of brackets and a plurality of driven members.
 39. The tiller assembly of claim 27, wherein the tiller assembly is a snow tiller and the ground shaping element is a rotatable drum with a cover.
 40. The tiller assembly of claim 27, in combination with a vehicle.
 41. The tiller assembly of claim 40, wherein the vehicle is a tracked vehicle and the tiller is a snow tiller.
 42. A method of working the surface of the ground, comprising: providing a tiller assembly having a ground shaping element and a finishing element with a chamber defined therebetween, wherein the finishing element is supported by a bracket; tilting the finishing element to change the volume of the chamber by moving the bracket in an arc with respect to the surface of the ground; operating the ground shaping element to grind the surface; and driving the tiller assembly across the surface to drag the finishing element over the surface and provide a finished texture to the ground.
 43. The method of claim 42, wherein tilting the finishing element includes driving a hydraulic cylinder by selectively energizing a hydraulic fluid in the hydraulic cylinder.
 44. The method of claim 42, wherein tilting the finishing element includes moving the bracket about a pivot point spaced from the bracket.
 45. The method of claim 42, wherein driving the tiller includes towing the tiller assembly from a vehicle. 